The present invention relates to fabrication process techniques, for example, semiconductor devices and the like. In particular, it relates to techniques for performing film deposition using fluids that have an organometallic compound as the main component (organometallic fluids).
In recent years, demands for further integration and miniaturization of the semiconductor devices have increased. In response to these demands, there has been a remarkable switch from aluminum-based materials to copper-based materials being used as interconnect material or line material in the film deposition process of manufacturing semiconductor devices.
A method of depositing a film using a material containing such types of copper, that has been put into practice includes, for example, metalorganic chemical vapor deposition (MOCVD), which is performed by vaporizing an organometallic compound (that is usually fluid at room temperature and under normal pressure) such as (hfac)Cu+1(tmvs), introducing it to the process chamber, and causing a pyrolytic decomposition reaction to occur on a wafer being held in said process chamber so that a thin film can be deposited.
Such conventional MOCVD processes thus provide superb step coverage and are extremely effective in the fabrication of very thin films. However, with these MOCVD processes, at times when it is necessary to guarantee a certain layer thickness, for example during the step of filling in contact holes, problems develop due to the lack of accuracy. It takes time to fill in the hole completely since there is a limit to the thickness of the layer that can be accumulated within a certain length of time due to the low amounts of the organometallic compound itself existing in the process chamber, which results from the low pressure in the process chamber. There is an additional danger of the vaporized organometallic compound reacting inside the supply pipeline and clogging the pipes.
Accordingly, the present invention aims to provide a film deposition method and apparatus, which use an organometallic fluid that can deposit a film with superb filling-in characteristics.
In order to fulfill the objective mentioned above, the inventors considered many variables. As a result, they found that the pyrolytic decomposition reaction of organometallic fluid occurs by heating it even if it does not vaporize, thus resulting in film formation. From this, the inventors considered methods of applying organometallic fluid while heating the wafer; however, with this method, they came to the conclusion that it is difficult to flow in the organometallic fluid entirely into holes and trenches, such as the contact holes that are microstructured on the surface of the semiconductor wafer resulting in a development of vacancies in the holes.
Accordingly, a film deposition method of depositing a film by adhering an organometallic fluid onto a to-be-processed body such as a semiconductor wafer, and subjecting it to a pyrolytic decomposition reaction, is characterized by the first step of adhering a solvent, which is used to mix with an organometallic compound, onto a to-be-processed body and adhering the organometallic fluid onto said to-be-processed body after the first step is finished.
In this manner, when the organometallic compound is adhered onto the to-be-processed body while the surface of the to-be-processed body is being wet with the solvent that is mixed with the organometallic compound, said fluid is highly adaptive to the solvent that has been adhered, permeating over the entire area. Accordingly, the fluid containing the organometallic compound evenly flows into the holes and trenches microstructured on the to-be-processed body. Therefore, the possibility that vacancies develop in the minute pattern is very low, so that it is possible to deposit a film with favorable filling-in characteristics.
It is noted here that xe2x80x98adhesionxe2x80x99 represents a broad idea that includes cases where a to-be-processed body is immersed into a fluid; cases where it is atomized and then applied to the body; or cases where it is applied using a roller, etc.
In the above film deposition method, the organometallic fluid may be of solely an organometallic compound; alternatively it may be a mixture of an organometallic compound and a solvent added to it. In this case, the solvent that is used by itself in the first step may be used to generate the organometallic fluid.
A copper-ketonato metal complex, for example, is used as the organometallic compound, and an aliphatic saturated hydrocarbon is used as a solvent that is mixed with the organometallic compound.
Furthermore, a film deposition apparatus, according to the present invention, which is suitable for the implementation of the above-mentioned film deposition method, is comprised of organometallic fluid adhering means, which adheres a fluid that is mixed with an organometallic compound onto a to-be-processed body; organometallic fluid adhering means, which adheres a fluid including an organometallic compound onto the to-be-processed body; and control means, which controls the solvent adhering means and the organometallic fluid adhering means so as to adhere the solvent onto the to-be-processed body and then adhere the organometallic fluid onto the to-be-processed body.